<ARTICLE> 5
<LEGEND>
This schedule contains summary financial information extracted from the
June 30, 1998 quarterly consolidated financal statements and is qualified
in its entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               JUN-30-1998
<CASH>                                           5,598
<SECURITIES>                                         0
<RECEIVABLES>                                   89,974
<ALLOWANCES>                                     1,911
<INVENTORY>                                      3,849
<CURRENT-ASSETS>                               128,106
<PP&E>                                         735,653
<DEPRECIATION>                                 257,896
<TOTAL-ASSETS>                                 607,975
<CURRENT-LIABILITIES>                           94,384
<BONDS>                                        209,920
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           316
<OTHER-SE>                                     238,612
<TOTAL-LIABILITY-AND-EQUITY>                   607,975
<SALES>                                              0
<TOTAL-REVENUES>                               477,051
<CGS>                                                0
<TOTAL-COSTS>                                  451,859
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0<F1>
<INTEREST-EXPENSE>                               8,013
<INCOME-PRETAX>                                 18,201
<INCOME-TAX>                                     7,371
<INCOME-CONTINUING>                             10,830
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    10,830
<EPS-PRIMARY>                                      .34
<EPS-DILUTED>                                      .34
<FN>
<F1>Provision for Doubtful accounts included in costs and expenses applicable
to revenues.
</FN>